| True North Mechanical Ltd. | Construction | 2016 |
| True Property Options Ltd | Real estate | 2017 |
| True Talent Traders Limited | Administrative & support | 2024 |
| True Warrior Promotions Limited | Other services | 2008 |
| True-Blue Construction Ltd | Construction | 2022 |
| Truenorth Asset Management Limited | Professional & scientific | 2017 |
| Truenorth Metrics Ltd | Construction | 2025 |
| Truetek Services Limited | Information & communication | 2014 |
| Truevalue Market Ltd | Wholesale & retail | 2025 |
| Trueworkflow Ltd | Information & communication | 2025 |
| Trufy Limited | Wholesale & retail | 2025 |
| Truline Healthcare Ltd | Administrative & support | 2018 |
| Truline Workforce Ltd | Administrative & support | 2026 |
| Trulocom Limited | Financial services | 2022 |
| Truman Securities Limited | Hospitality | 2015 |
| Trunest Ltd | Real estate | 2024 |
| Trunity 2 Ltd | Real estate | 2024 |
| Trunity Ltd | Real estate | 2023 |
| Trusmiles Limited | Health & social care | 2025 |
| Truss Services Limited | Administrative & support | 2021 |
| Trust Business Card Ltd | Administrative & support | 2025 |
| Trust the Process Ltd | Professional & scientific | 2015 |
| Trustax (UK) Limited | Professional & scientific | 2000 |
| Trustcareuk Ltd | Administrative & support | 2023 |
| Trustchain Ltd | Information & communication | 2017 |
| Trustdrive Motors Ltd | Wholesale & retail | 2026 |
| Trusting Hearts Care UK Ltd | Administrative & support | 2026 |
| Trustlink Errand & Logistics Limited | Transport & logistics | 2026 |
| Trustpath Social Ltd | Professional & scientific | 2025 |
| Truth Real Estate Limited | Real estate | 2021 |
| TS Film Productions Limited | Information & communication | 2021 |
| TS Grover Convenience Store Ltd | Wholesale & retail | 2014 |
| TS Land Investments Limited | Real estate | 2022 |
| TS Leisure Vehicles Limited | Wholesale & retail | 2020 |
| TS Management Limited | Real estate | 2021 |
| TS Site Investigation Ltd | Construction | 2023 |
| TS Transport Ltd | Transport & logistics | 2025 |
| TSA Limited | Wholesale & retail | 2020 |
| Tsalach Ltd | Wholesale & retail | 2021 |
| Tsantilis&Co Ltd | Professional & scientific | 2025 |
| Tsbuk Entertainment Ltd | Information & communication | 2019 |
| TSD Leicester Ltd | Transport & logistics | 2019 |
| TSF Productions Limited | Information & communication | 2021 |
| TSK Event Management Ltd | Hospitality | 2024 |
| TSK Mall Limited | Wholesale & retail | 2020 |
| Tsld Construction Ltd | Construction | 2019 |
| TSM Health Limited | Health & social care | 2012 |
| TSN (Northeast) Limited | Hospitality | 2022 |
| TSS Cleaning Limited | Administrative & support | 2019 |
| TSS Pharma Ltd | Health & social care | 2026 |
| TSW Port ST. Limited | Real estate | 2024 |
| TT Lifesciences Ltd | Other services | 2023 |
| TT Productions Group Limited | Other services | 2016 |
| Ttath Services Ltd | Professional & scientific | 2022 |
| TTG Director Exit Ltd | Professional & scientific | 2025 |
| TTG Options LLP | | 2001 |
| TTG Options Markets Ltd | Financial services | 2015 |
| TTM Holdings Limited | Financial services | 2016 |
| Tual Ltd | Transport & logistics | 2018 |
| Tuana's Cafe Ltd | Hospitality | 2016 |
| Tuatara Real Estate Limited | Real estate | 2022 |
| Tuba Ltd | Wholesale & retail | 2018 |
| Tubby Baker Advertising Limited | Professional & scientific | 2023 |
| Tubby Baker Holdings Limited | Financial services | 2024 |
| Tuby Construction Ltd | Construction | 2020 |
| Tucatrafic Ltd | Transport & logistics | 2018 |
| Tudor Care Limited | Health & social care | 2003 |
| Tudor Holdings Group Limited | Other services | 2020 |
| Tudor Invest Limited | Real estate | 2012 |
| Tudor Motor Group Ltd | Wholesale & retail | 2025 |
| Tudor Place Freehold Company Limited | Households | 2012 |
| Tudor Place Management Company Limited | Households | 1997 |
| Tudor Place Residents Association Company Limited | Households | 1997 |
| Tudorwell Limited | Wholesale & retail | 1991 |
| Tufffinds Ltd | Wholesale & retail | 2025 |
| Tulip Aesthetics Clinic Limited | Health & social care | 2023 |
| Tulip Care Limited | Health & social care | 2005 |
| Tulip Roofing and Guttering Limited | Construction | 2026 |
| Tulja Enterprise Limited | Wholesale & retail | 2024 |
| Tullius Consulting Ltd. | Real estate | 2020 |
| Tullycommon Limited | Professional & scientific | 2016 |
| Tulpa Technologies Ltd | Information & communication | 2023 |
| Tulsi Investments Limited | Real estate | 2014 |
| Tulsi Management Limited | Real estate | 2019 |
| Tulstik Properties Limited | Real estate | 1998 |
| Tumi (UK) Gold Ltd | Real estate | 2013 |
| Tumi (UK) Real Estate Limited | Real estate | 2016 |
| Tunald Developments LLP | | 2007 |
| Tunbridge Wells Restaurants Limited | Hospitality | 2020 |
| Tuncel Investment Limited | Real estate | 2021 |
| Tuning LAB London Ltd | Wholesale & retail | 2023 |
| Tunnel Lounge Limited | Hospitality | 2017 |
| Tunnelwood Limited | Administrative & support | 1997 |
| Tunsu Transport Ltd | Transport & logistics | 2026 |
| TURBOCHARGER5 Ltd | Wholesale & retail | 2019 |
| Turf Doctor Specialists Limited | Administrative & support | 2017 |
| Turf Labs Limited | Manufacturing | 2019 |
| Turn Property Solutions Ltd | Real estate | 2023 |
| Turner and Goldrich Limited | Health & social care | 1973 |
| Turner Professional Services Ltd | Information & communication | 2008 |